Telephone-exchange system.



No. 650,548. Patented May 29, I900.

- W. SMITH.

TELEPHONE EXCHANGE SYSTEM.

(Application filed June 9, 1899.)

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No. 650,548. Patented May 29, I900. W. SMITH.

TELEPHONE EXCHANGE SYSTEM.

(Apglication filed June 9, 1899.\

2 Sheets-Sheet 2.

(No Model.)

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UNITED STAirEs lPiarENT Orrin.

"WALTON SMITH, OF RIDLEY PARK, PENNSYLVANIA, ASSIGNOR TO JAMES S. THOMPSON, OF NORTH TONAVVANDA, NEW YORK.

TELEPHONE- EXCHANGE SYSTEM.

SPECIFICATION forming part of Letters Patent No. 650,548, dated May 29, 1900. Application filed June 9, 1899. Serial No. 719.879. (No model.)

To aZZ whom it may concern: the same or is raised by a spring h when the Be itknown that LXVALTON SMITH, a citizen telephone is removed therefrom. All of these of the United States, residing at Ridley Park, parts may be of ordinary construction. in the county of Delaware and State of Penng is a ground-contact which is connected by 5 5 sylvania, have invented new and useful Ima wire 9' with the ground G and which is enprovements in Telephone-Exchange Systems, gaged by the switch-lever when the latter is of which the following is a specification. depressed. One end of the generator-coils is This invention relates to a telephone-exconnected with a generator-contact b, which change system in which the electric generator is engaged by the switch-lever when the latter IO or source of energy for operating the speakis depressed. The other end of the generaing apparatus of the different subscribers is tor-coil is connected by a wire 0 with one side all located at the central office instead of 10- of the bell-coils. One side of the transmitteris eating a generator for this purpose at each connected by a wire d with the opposite side subscribers station, this arrangement of the of the bell-coils, and the other side of the I 5 generators being commonly known as the transmitter is connected by a wire (1 with central-energy system. 4 one end of the primary induction-coil). The One of the objects of this invention is to opposite end of the primary coil is connected provide a generator system of this character by a wire d with a transmitter-contact 01 in which the electric energy is applied uni which is engaged by the switch-lever when 2o formly to the speaking apparatus of two parthe latter is raised. The ends of the coil in the ties who are conversing and is only in use telephone or receiver are connected by wires when two parties are connected with each f f with the secondary induction-coil f other. I and K represent the main lines, whereby Myinventionhas thefurtherobjectto avoid each subscribers station is connected with v 25 the induction between the main lines of the the central oflice and with another subscribsubscribers and adjacent electric wires,there-- ers station. The wire I is connected with by improving the transmissionof speech and the bell-coils on the side opposite to that with permitting conversation to be carried on withwhich the generator-coil is connected, and it out interference from cross-talking or other is connected with the transmitter-wire cl, so o electrical disturbances. that the current from the wire I can pass In the accompanying drawings, consisting either through the bell-coils and generator, of two sheets, Figure 1 is a sectional View which constitute the essential parts of the showing my improvements applied to a telesignaling apparatus, or through the transmitphone-switch system in which the main line ter and primary induction-coil, which form 5 is opened when the subscriber calls up the part of the talking apparatus. The wire K central office. Fig. 2 is a fragmentary view is connected only with the switch-lever. showing the circuits of the operators listen- \Vhen the receiver is hung upon the switching and talking apparatus. Fig-3 is a fraglever, the latter is disengaged from the transmentary sectional View showing my improvemitter-contact d and depressed into engage- 9o 40 ments applied to a telephone-switch system ment with the ground and generator contacts in which the main line is not opened when a g and b, and when the receiver is removed subscriber calls up the central oflice. the switch-lever israised by the spring it out Like letters of reference refer to like parts of engagement with the contacts 9 and b and in the several figures. into engagement with thecontact d 5 5 Referring to Fig. 1, A represents the inclos- The annunciators of the subscribers are ing case of a subscribers apparatus; B, the mounted on upright switchboards Z at the signal-generator; O, the bellcoils; D, the central office, and each consists, essentially, telephone receiver; E, the microphone or of a plunger Z, provided at its front end with transmitter; F, the induction-coils, and H a visual indicator head or button, a pivoted 10c 50 the vertically-movable switch-lever, which is catch Z adapted to engage with the plunger depressed when the telephone is hung upon and hold the same in a retracted position, an

armature Z connected with said catch, a pair of coils 1*, which when energized attract said armature and disengage the catch from the plunger, and a spring Zfiwhereby the plunger is projected when released.

M represents the couplingjacks, one or more of which are arranged in each subscribers line at the central oilice and which receives the plug of the operators listening or signaling apparatus or the coupling-plugs N of other subscribers. These jacks are arranged on the vertical switchboard and may be of any usual or well-known construction each of the jacks shown in Fig. 1 consisting, essentially, of a socket-contactm and a springcontact m, which is adapted to be engaged with and disengaged from the socket-contact.

The wire I of each subscriber runs directly to the socket-contact m of its coupling-jack. Theother member m of its coupling-jack is connected by a wire 0 with one end of the subscribers annunciator-coils, the opposite end of the annunciator-coils being connected with an insulated contact 0', which is adapted to be engaged by a contact 0 on theplunger when the latter is in its retracted position.

The coupling-plug N of each subscriber is provided with two contacts 7t 91, which are adapted to engage, respectively, with the two members m m of the coupling-jack of an other subscriber.

p prepresent the two members of a divided contact-seat, which are adapted to support the plug of the subscriber when not in use and which are electrically connected by a bridge 19 formed, preferably, by the metallic base on the lower end of the coupling-plug. When the coupling-plug is not in use, the same is held with the bridge 12 on its base against the contacts 19 p by a cord I, which is connected with its ends to the plug and the switchboard and a weight 11 provided with a roller, which engages with the bight of the cord. Two wires 19 p are arranged in the cord. The wire 12 is connected at one end with the plug-contact n and at its other end with the main Wire K and by a branch 'wire 1) with the bridge-contact p. The other cord-wire p is connected at one end with the plug-contact n and at its other end by a wire 197 with the frame of the annunciator and by a branch wire 19 with the b-ridgecontactp. The plunger carrying the contact 0 is in metallic contact with the annunciator-frame to which the wire 19 is connected, so that the frame and plunger form a part of the electric conductor.

Q represents an electric generator or battery which supplies the current for operating the talking and listening apparatus of two connected subscribers. Each subscriber is preferably provided with an individual battery of sufficient power to supply the necessary current for operating the talking and listening apparatus of the two subscribers having the longest lines in the system. The battery is arranged at the central office and is included in one of the wires of the plug-cord,

the same being shown included inthe cordwire 19 in Fig. 1.

The operators listening and talking apparatus, as shown in Fig. 2, consists, essentially, of a telephone or receiver R, a transmitter S, a pair of induction-coils T, an electric battery or generator U, and a coupling-plug V. The coupling-plug V is provided with a central contact 12 and a surrounding insulated contact-sleeve v, and these contacts are respectively connected by main circuit-wires v v with one end of the primary induction-coil i and one side of the transmitter. The other end of the primary induction-coil is connected with the opposite side of the transmitter by a wire a, which includes the electric battery U. The opposite ends of the secondary induction-coil t are connected by wires 1* r with opposite ends of the coil in the receiver or telephone and complete the operators local circuit.

If a subscriber whose line is in normal condition operates his signaling apparatus for calling up the central oflice, the circuit is as follows: Beginning at the contact I) on one side of the generator, the current passes successively through the switch-lever H, main wire K, branch wire 1), contact p, bridge 21 contact 19', branch wire p wire 13, annunciator-frame, plunger Z, contacts 0 o, ann'unciator-coils, wire 0, coupling-jack contacts m m, main wire I, bell-coils, wire 0, and through the generator-coil to contact Z). This current energizes the annunciator-coils of the subscriber at the central office, therebyreleasing the plunger and permitting the same to be projected by its spring, whereby the operator is informed that the subscriber has called up, and at the same time the circuit is broken by the separation of the contacts 0 0 and the subscriber by reason of his bell stopping ringing is informed that his call has been received at the central office. This signal from the subscriber to the central 0ffice is sent over a metallic circuit, notwithstanding that the subscribers ground is ,connected with the circuit at this time. The construction and operation of this signaling apparatus is the same as that shown and described in my application for Letters Patent, Serial No. 710,757,- filed March 28, 1899. The operator now shoves in the plunger of the calling subscriber, so as to close the break in the line at the annunciator, and at the same time the operator shoves her coupling-plug V into the coupling-jack of the calling subscriber and in so doing separates the contacts m m of the jack and engages the plug-contacts U r with the jack-contacts 'm m, respectively, thereby looping the operaoperators plug-contact 4;, wire v transmitter S, wire a, including battery U, primary in duction-coil t, wire r plug-contact '0, jack contact m, wire 0, annunciator-coils Z contacts 0 0 plunger and frame, wire p wire p contact 1), bridge 12*, contact 10, wire 1), main wire K, switch-lever H, contact (Z wire (Z primary induction-coil f, and wire d to the opposite side of the transmitter. the subscriber or the operator talks into his respective transmitter, the undulations produced thereby in the main electric circuit are reproduced by the induction-coils in the local electric circuits, which include only the receivers and the secondary induction-coils of the subscriber and operator. It will be observed that when the subscriber and operator are thus connected the electric current for the main circuit between these parties is supplied wholly by the battery U of the operators talking and listening set, and this current is distributed uniformly between both the subscriber's and operators apparatus, so that both parties can hear equally well. After learning with whom the calling subscriber wishes to be connected the operator withdraws her listening and talking plug V from the calling-subscribers coupling-jack and then introduces the plug of her signaling apparatus into the coupling-jack of the subscriber who is wanted and rings him up. Any suitable signaling apparatus may be used in this system by the operator, that shown in the drawings being the same as that shown in my aforesaid application for Letters Patent, Serial No. 710,757, filed March 28, 1899. After having signaled the called subscriber that he is wanted the operator disconnects her signaling-plug from his coupling-jack and the operator takes the couplingplug of the calling subscriber and shoves the same into the couplingjack of the called subscriber. By this act of the operator the circuit across the bridge-contacts p p of the calling subscriber are broken and the contact members at n of the calling-subscribefis coupling-plug are engaged, respectively, with the jack-contacts m m of the called subscriber. Assuming that subscriber No. 1 has called up No. 300 and that both subscribers after being connected remove their receivers from the switch-levers, a metallic talking-circuit is formed between the two subscribers, which is shown in Fig. 1 and which is as follows: Beginning at wire (Z on one side of the transmitter of subscribers station No. 1, the current passes successively through wire I, jackcontacts 172 m, wire 0, annunciator-coils Z" of subscriber No. 1, contacts 0 0 plunger and frame, wire p cord-wire p plug-contact n, coupling-jack contact on of subscriber No.300, main wire I, wire (I, transmitter E, wire (1, primary induction-coil f of subscriber No. 300, wire (2 contact (1 switch-lever H, main wire K, branch wire 1), contact 19, bridge-contact 19 contact n, branch wire 12*, wire p frame and plunger of subscribers annunciator No.

300, contacts 0 0, annunciator-coils, wire o,v

contact on of subscribers jack No. 300, contact n of subscribers plug No. 1, cord-wire 13 including battery Q, of subscriber No. 1, main wire K, switch-lever H, contact d wire (1 and primary induction-coil f to the opposite side of the transmitter of subscriber No. 1. When the subscriber talks into his transmitter, the undulations produced thereby in the main electric circuit are reproduced by the induction-coils in the local electric circuits, which include only the receivers and secondary coils of the subscribers,in the same manner as when the operator is talking to a subscriber. By arranging the battery, the transmitters, and the primary coils in the main circuit and the receivers and secondary coils in the local circuits the induced current through the secondary coils and receiver is confined to the subscribers or operators local circuits, thereby making it possible. to transmit speech more clearly and over a greater distance than heretofore. Inasmuch as the primary circuit of the induction-coils and transmitters of both the connected par ties are in circuit with the same battery in the main line, the current passing through nal to the central office, this current for this signal passing over a ground-circuit from one subscriber to another, as follows: Beginning at the ground of subscriber No. 1, the current, passes successively through the ground-Wire g, ground-contact g, switch-lever H, generator-contact b,generator-coils,be1l-coils, main wire I, jack-contacts m m, coils 1, contacts o 0 plunger Z and frame of subsoribers annunciator No. 1, wire p cord-wire p plugcontact a, jack-contact m, main wire I, bellcoils and generator-coils of subscriber No.300, generator-contact b, switch-lever H, groundcontact g, and ground-wire g to the ground of subscriber No. 300. This ringing-off circuit-includes only the annunciator-coils of the subscriber whose plug is in use, whereby the plunger of this subscriber only is projected and the respective operator is notified that the conversation is finished. The operator now withdraws the calling-subscribefis plug from the called-subscribefls coupling-jack and returns the plug with its base upon the contacts 19 19, so as to cross the same, and the operator also shoves in the plunger of the calling-subscribers annunciator, thereby restoring both subscribers lines to their'normal condition. Thisringing-offcircuitisthesame as in the application for Letters Patent referred to.

It will be observed that the battery Q of only one subscriber is in use for operating IIO the talking and listening apparatus of both subscribers which are connected. By arranging a battery Q in one of the plug-Wires of each subscriber the battery of that subscriber is included in the main circuit, whose plug is used in e'ltectinga connection between two subscribers, and the circuit of each battery is therefore always open unless its respective plug is coupled with the jack of another subscriber, thus avoiding wasting of the battery-power.

In the modification of my telephone-exchange system shown in Fig. 3 an annunciator W, with a pivoted indicator-apron w, is employed. This annunciator is so organized that the main line is not broken or opened by the annunciator when the subscriber sends a call to the central office, and the subscriber is therefore not notified that his call has been received, because his bell does not stop ringing. The annunciator-coils of both constructions shown in Figs. 1 and 3 are wound to a sufficiently-high resistance, so that the same cannot be operated by the transmitter-battery While the latter is placed in circuit when coupling two subscribers or when coupling a subscriber with the operator.

I claim as my invention- 1. The combination with a main circuit con-- necting a subscribers station and a central office and a local circuit arranged at the subscribers station, of a transmitter'arranged in the main circuit at the subscribers station, a receiver arranged in said local circuit, an-induction-coil having its primary included in the main circuit and its secondary included in said local circuit, a coupling-jack arranged in the main circuit at the central office, a

coupling-plug arranged at the central officeand connected with the main circuit by a branch line, a battery included in said branch Z line, and a switchwhereby said branch line and battery are cutoff from the main circuit when the plug is in its normal inoperative po closed and ungrounded at the central office, v and a local circuit arranged at the subscribers station, of a coupling-jack arranged in the main circuit at the central office, a transmitter arranged in one side of the main circuit, a receiver arranged in the local circuit, an induction-coil having its primary included in the side of the circuit containing the transmitterand its secondary included in the local circuit containing the receiver, said transmi-tter, receiver and induction-coil forming the subscribers speaking apparatus, a signaling apparatus arranged at the subscribers station in the same side of the circuit containing the transmitter, a switch whereby either the subscribers signaling apparatus and ground or the subscribers speaking apparatus are connected with the metallic circuit, an annunciator arranged at the central oftice in the opposite side of the main circuit, a coupling-plug connected by branch lines with the main circuit between the annunciator and the subscribers station, bridge-contacts arranged in the main circuit on opposite sides of the plug branch lines and adapted to be connected and disconnected by av bridge on the plug, and a battery included in one of the plug branch li-ncs,su-bsiantially as set Y forth.

W'itness my hand this 6th day of May, 1809.

WALTON SMITH. Witnesses:

W. GOULD SMITH, ROBT. CARNS. 

